1. Technical Field
The present invention pertains to athletic shoes, particularly golf shoes, and to improved traction cleats removably connected to the outsole of such shoes. The invention further pertains to improved methods of fabricating the cleats, installing the cleats on shoe outsoles, and the operation of the cleats to provide traction.
2. Discussion of the Prior Art
It is also known in the prior art to provide a locking mechanism associated with the connection of the cleat to the shoe mounted connector to prevent inadvertent loosening of the connection and removal of the cleat. Examples of such locking mechanisms are found in U.S. Pat. Nos. 5,974,700 (Kelly), 6,823,613 (Kelly et al), and 7,107,708 (Kelly et al), and the disclosures from these patents (hereinafter referred to as the “Kelly patents” are also incorporated herein by reference in their entireties. Among these locking mechanisms is one sold under the trademark FAST TWIST® comprising radially facing locking formations on the cleat and receptacle, respectively, operative to inter-engage when the stem has been screwed into the socket or connector of the shoe-mounted receptacle. One of the locking formations, typically on the receptacle connector, comprises an annular array of radially projecting locking teeth, while the other, an annular array of locking posts, typically on the cleat, includes a radially-facing lead-in ramp and recess. The teeth, during stem rotation, ride over a lead-in ramp before snapping into a recess on the locking post. A stop member on the post resists inadvertent relative rotation between the stem and receptacle connector and loosening of the installed cleat. The locking mechanism allows the cleat to be unscrewed for removal and replacement upon exertion of a predetermined level of torque (i.e., typically by means of a special cleat wrench), resulting in the resilient yielding of the locking posts. Both the teeth and posts are typically axially-extending members surrounding the threaded stem and socket.
There are several removable cleats being commercialized that utilize both the FAST TWIST® attachment mechanism and dynamic traction elements. Typically, these cleats utilize a base made from a first relatively hard polymer which includes a body member having thread form and a circular array of locking posts angularly spaced and uniformly arranged around a circular hub. A second softer and more resilient polymer material provides the dynamic or static traction elements or legs that extend downwardly and outwardly from the circular hub. The dynamic traction legs provide traction by 1) tangling with grass; 2) deflecting upwardly toward the outsole of the shoe and trapping grass between the upper surface of the traction leg and the sole of the shoe; and 3) when the shoe slips sideways, absorbing or opposing the force of the lateral slip and folding inwardly on themselves toward the cleat axis, whereby their downward or vertical extension of the elements resiliently increases from the extension in the unflexed position.
Conventionally, the requirement that the dynamic traction elements extend from the periphery of the circular hub serves to restrict the downward or vertical extension that the traction element can achieve when providing traction against lateral slip. In U.S. Patent application Publication No. 2008/0072460, published Mar. 27, 2008 there is disclosed a technique involving molding the softer and flexible body having the dynamic legs or elements separately from the harder and rigid hub, which includes static (i.e., non-flexing) traction elements or legs, and then securing the hub and body by a molded connecting piece (i.e., by other than molding the hub and legs as an integral unit). This method, in theory, allows the dynamic elements to be attached closer to the central longitudinal axis of the cleat (rather than at the hub periphery), thereby moving the dynamic element flexure point during lateral slip from the hub periphery to a location closer to the hub central axis. As a result, for the same overall height or vertical dimension of a cleat, the dynamic traction elements can be made longer from their proximal ends (i.e., the points of attachment to the hub) to their distal tips. The longer the lengths of the dynamic traction elements, the greater is their ability to flex as they bend inward toward the axis and extend outwardly to provide increased traction during lateral slip. However, the method of separately molding the dynamic elements unit and then attaching that unit to the hub by means of a separate connector is costly and results in the possibility of the traction element unit body becoming detached from the hub body.
Another limitation in the design of prior dynamic traction cleats is the need to provide a substantially solid or continuous circular hub in order to accommodate the above described FAST TWIST® locking mechanism. More specifically, the FAST TWIST® locking posts disposed on the cleat hub near its peripheral edge are equi-angularly spaced at very short angular distances about the threaded stem in order to work in concert with the locking teeth on the shoe-mounted receptacle. This leaves little leeway for varying the hub from the conventional continuous circular configuration; that is, the hub material must be continuous in order to provide support the entire array of locking posts on its top surface near the hub peripheral edge.